EP0175078A2 - Device and method for production of ultra-fine, rapidly solidified, metal powders - Google Patents
Device and method for production of ultra-fine, rapidly solidified, metal powders Download PDFInfo
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- EP0175078A2 EP0175078A2 EP85108528A EP85108528A EP0175078A2 EP 0175078 A2 EP0175078 A2 EP 0175078A2 EP 85108528 A EP85108528 A EP 85108528A EP 85108528 A EP85108528 A EP 85108528A EP 0175078 A2 EP0175078 A2 EP 0175078A2
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- Prior art keywords
- melt
- gas
- ultra
- atomization
- fine powder
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
- B22F9/00—Making metallic powder or suspensions thereof
- B22F9/02—Making metallic powder or suspensions thereof using physical processes
- B22F9/06—Making metallic powder or suspensions thereof using physical processes starting from liquid material
- B22F9/08—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying
- B22F9/082—Making metallic powder or suspensions thereof using physical processes starting from liquid material by casting, e.g. through sieves or in water, by atomising or spraying atomising using a fluid
Definitions
- the present invention relates to methods and equipment for producing ultra-fine, rapidly solidified powders directly from a melt, and uses a soluble gas/subsonic, supersonic, or ultrasonic gas atomization technique.
- the present invention provides both a device and method for generating rapidly solidified metal powders with an average particle size significantly less than 10 ⁇ m directly from a melt.
- the invention includes a gas atomization die having an orifice through which the liquid metal passes to create a rapidly solidified. ultra-fine powder. This die may rely solely on heat conducted from the molten metal or heat provided by an internal heater to maintain the temperature of the orifice at a level sufficient to avoid melt freeze-off during operation.
- the molten metal to be atomized is made to contain soluble species, such as hydrogen, nitrogen, or carbon and oxygen in carbon steel, which with either leave solution independently or combine to form gaseous products which leave solution as the metal cools.
- This soluble gas atomization/impinging gas atomization technique is iniquely capable of generating rapidly solidified metal powders with an average particle size in the submicron range.
- FIG. 1 a perspective view is shown of the atomization system, consisting of the gas atomization device 100, crucible or furnace melt containment vessel 200, and fine powder collection system.
- the letter consists of a rapid cooling chamber 300, cyclone separator 400, second stage fine powder removal device 500, ultra-fine powder filter 600, and gas pump 700.
- Gas atomization dies per se, are known in the art and consist of an orifice through which the melt passes, and one or more high pressure gas jets for breaking up and atomizing the melt as it passes out of the die orifice.
- the gas atomization die 100 can be of subsonic. supersonic, or ultrasonic design.
- a subsonic gas atomization device is illustrated here in Figure 1.
- Ultra-fine metal powder 140 is produced by passing pressurized gas 150, such as argon, nitrogen, etc., through the atomization die 100. This atomization gas 150 is delivered to the atomization die 100 via a gas delivery passage 160 through the body of the die 100.
- This high pressure gas 1 50 exits the atomization die 100 at high velocity, thereby aspirating the melt 210 through the atomization die orifice 111.
- the molten metal 210 is atomized and rapidly cooled by the impinging, high velocity, atomization gas jets 114 ( Figure 2).
- the atomized droplets 140 are further disintegrated into ultra-fine powders by the rapid generation of gas within the droplets.
- the gas which "explosively" disintegrates the already atomized droplets, is soluble in the liquid melt but its solubility is a strong function of temperature and, therefore, gas is rapidly generated within each droplet as it cools upon exiting the atomization die 100.
- the solubility of nitrogen in iron is illustrated in Figure 4, by way of example.
- the solubility of nitrogen in iron is a function of temperature, and changes abruptly and significantly at specific temperatures where phase transitions occur. Referring to Figure 4, one can expect significant soluble gas evolution either upon rapidly cooling of the melt and/or when structural phase changes occur in the melt at specific transition temperatures. Consequently, the rate of soluble gas evolution and subsequent extent of soluble gas atomization is a function of the rate at which the melt is cooled.
- the melt 210 to be atomized is located above the atomization die 100 and the rapid cooling chamber 300.
- the atomization die 100 could access the crucible or furnace 200 from the bottom, top, or side. It is also possible for the crucible 200 and atomization die 100 to be located entirely within the cooling chamber 300.
- the melt 210 Before the atomization process begins, the melt 210 must be saturated with a soluble gas 220. If the crucible 200 is closed, the melt 210 can be supersaturated by holding the soluble gas 220 at elevated pressure above the melt 210.
- gases including argon, nitrogen, and hydrogen, which are soluble in liquid metals, can be used. These soluble gases can be introduced into the melt 210 via a gas bubbling mechanism and/or can simply be held at static pressure over the melt 210 if the crucible 200 is closed.
- the soluble gas comes out of solution within the atomized melt droplets, expands rapidly, and causes the metal to further disintegrate into ultra-fine powder.
- a melt can be supersaturated with soluble gas by pressurizing the melt containment vessel with the gas to be dissolved.
- the head pressure is used to propel the melt material through a transport tube into an evacuated chamber.
- the gas is evolved from the melt as it exits the transport tube into the evacuated chamber due to the low partial pressure of the soluble gas surrounding the melt stream in the evacuated chamber.
- the dissolved gas expands within the melt as it leaves the transport tube causing it to be atomized.
- the abrupt change in the over-pressure of the soluble gas causes the gas to be evolved from the melt and atomizing it. In expanding, the gas cools thus cooling the melt. This cooling rate is low, typically 10 to 102 °K/s.
- the melt containing soluble gas is atomized and rapidly cooled by the gas atomization process.
- the melt is atomized into a chamber 300 which need not be evacuated. Because the melt is rapidly convectively cooled by the impinging gas atomization jet, the evolution of soluble gas from the melt is driven predominantly by the temperature change of the atomized droplets. Soluble gas will be evolved in especially significant quantities at phase change temperatures such as correspond to the solidus-liquidus line.
- the melt 210 may contain soluble gases 220 and/or elemental components which will combine, on cooling of the melt 210, to generate a gas.
- soluble gases 220 and/or elemental components which will combine, on cooling of the melt 210, to generate a gas.
- One example of this latter case is carbon and dissolved oxygen in carbon steel.
- the carbon reacts with the dissolved oxygen to form carbon monoxide gas.
- carbon monoxide only has a negligible solubility in solid carbon steel, it is rapidly evolved upon cooling and solidification and can generate tremendous internal gas pressures if trapped within the solid steel.
- This type of gas generation upon cooling of the melt is very desirable in the present invention.
- This phenomena of carbon monoxide generation during cooling or solidification of carbon steel is well known in steelmaking. It is generally avoided by "killing" the melt will aluminum which reacts with the oxygen to form solid aluminum oxide particulates.
- a soluble gas may also be generated within the melt 210 by introducing a specific constituent which reacts in the melt 210 to generate a soluble gas.
- a specific constituent which reacts in the melt 210 to generate a soluble gas.
- This method is steam, which, when bubbled through carbon steel, reacts to form soluble hydrogen and oxygen. As the melt cools, the oxygen is available to combine with carbon present in the steel to form insoluble carbon monoxide gas. In addition, the hydrogen will also leave solution upon cooling of the melt and contribute to the soluble gas atomization component of the current atomization invention.
- a further example would be the addition of methane to carbon steel, for example. Here the methane reacts to form soluble carbon and hydrogen in the melt.
- Figure 1 also illustrates the powder collection system.
- This consists of a rapid cooling chamber 300 within which the ultra-fine powders 140 are generated and rapidly cooled by the impinging atomization gas jet.
- This cooling chamber 300 can be designed to accommodate multiple atomization dies.
- the cooling chamber's dimensions are such so as to allow the powders 140 to solidify and cool sufficiently before passing to the cyclone separator 400.
- the atomized powders are carried by the atomization gases, or pneumatically transported, from the cooling chamber 300 to the cyclone separator 400. Powders in the micron size range and larger are removed from the transport gas by the cyclone separator 400.
- a parallel series of cyclone separators could be used to selectively separate the powder 140 by average particle size.
- Ultra-fine powder 140 in the submicron particle size range will pass through the cyclone separator 400 with the carrier gas to the second stage powder recovery unit 500.
- This unit may consist of magnetic. electrostatic, impact, or solution separator. Any powder failing to be removed by the second stage powder recovery unit 500 will pass on to a filter 600 in the gas transfer line. This fine grade filter 600 will remove all powder residue from the atomization gas 150 before it passes on through the gas pump 700 and out of the system.
- the soluble gas/gas atomization process for generating ultra-fine, rapidly solidified powders is initiated by first introducing a soluble gas 220 into the melt 210, Figure 1.
- the melt crucible or furnace 200 can be contained within a pressure vessel 250.
- the amount of soluble gas 220 in the melt 210 can be increased by maintaining the soluble gas at high pressure over the melt 210.
- a relief valve 260 is desirable to avoid building up excessive pressure within the vessel 250.
- the stopper rod 270 which restricts melt flow to the atomization die 100, is withdrawn. Simultaneously, high pressure atomization gas 150 is supplied to the atomization die 100.
- the melt flow through the atomization die 100 is assisted by gravity, the head pressure within the containment vessel 250, and the aspiration effect of the atomization gas 150 through the die 100.
- the melt 210 exits the die 100 it is atomized by the impinging gas jet 114, Figure 2.
- This gas atomization process not only atomizes the metal exiting the die 100, but also conductively cools the atomized droplets as well. Consequently, the soluble gas within the melt comes out of solution rapidly, expands, and further disintegrates the atomized droplets into ultra-fine powder 140.
- the atomized ultra-fine powder 140 in the cooling chamber 300 is carried by the gas used in the atomization process.
- This fine powder aerosol 140 exits the cooling chamber and enters the cyclone separator 400 where all powder particles larger than roughly a micron in diameter are removed.
- the submicron powder is transported by the gas flow from the cyclone 400 to the secondary powder collection device 500.
- This unit may consist of a magnetic, electrostatic, fluid. or other fine particle separator. Residual powders are removed from the carrier gas by an in-line fine particle filter 600.
- the gas pump 700 aids in initiating the gas flow from the cooling chamber 300 and on through the powder removal and collection system.
Abstract
Description
- The present invention relates to methods and equipment for producing ultra-fine, rapidly solidified powders directly from a melt, and uses a soluble gas/subsonic, supersonic, or ultrasonic gas atomization technique.
- Several commercial techniques for producing fine, rapidly solidified metal powders are well described and characterized in the technical literature. These include sonic and ultrasonic gas atomization, rotating electrode, and rotating cup/dish techniques which produce various metal powders with an average particle size generally in excess of 10 micrometers (pm).In each of these processes, liquid metal is atomized and rapidly solidified at cooling rates in excess of 10 °K/s and up to 106 °K/s. The fine powders so generated can consist of meta-stable metallurgical phases and, either singularly or when compacted, can exhibit unique mechanical, electrical, magnetic, and chemical properties. Commercial applications of rapidly solidified and other fine metal powders include the use of:
- a. aluminum powders as a solid rocket fuel,
- b. superalloy powders for high performance turbine engine blades.
- c. copper and precious metal powders with viscous fluids to form electrically conductive pastes, and
- d. iron powder as a reprographic carrier and magnetic recording medium.
- This list is intended to provide a range of examples of commercial applications of fine metal powders and is not meant to be exhaustive. The availability of rapidly solidified fine metal powders in large quantities with a particle size of less than 10 pm would enhance current applications as well as also generate new commercial applications.
- The present invention provides both a device and method for generating rapidly solidified metal powders with an average particle size significantly less than 10 µm directly from a melt. In a preferred embodiment, the invention includes a gas atomization die having an orifice through which the liquid metal passes to create a rapidly solidified. ultra-fine powder.This die may rely solely on heat conducted from the molten metal or heat provided by an internal heater to maintain the temperature of the orifice at a level sufficient to avoid melt freeze-off during operation. The molten metal to be atomized is made to contain soluble species, such as hydrogen, nitrogen, or carbon and oxygen in carbon steel, which with either leave solution independently or combine to form gaseous products which leave solution as the metal cools. The rapid generation of this gas phase within the fine metal droplets as they rapidly cool upon exiting the gas atomization die causes the gas atomized metal droplets to further disintegrate into an ultra-fine powder with an average particle size significantly less than 10 µm. This soluble gas atomization/impinging gas atomization technique is iniquely capable of generating rapidly solidified metal powders with an average particle size in the submicron range.
- These and other objects and features of the invention will be more readily understood by consideration of the following detailed description given with the accompanying drawings.
- Figure 1 is a schematic overview of the ultra-fine powder generation facility consisting of the melt containment vessel, gas atomization device, rapid cooling chamber, and powder collection and recovery system.
- Figure 2 is a detailed view of a preferred embodiment of the invention showing the main features of the gas atomization die.
- Figure 3 is a detailed view of another preferred embodiment of the invention which illustrates the gas atomization die equipped with an orifice heating element of eliminate freeze-off during operation.
- Figure 4 illustrates the temperature dependence of the solubility of gas in a metal, in this case nitrogen in iron.
- The preferred embodiments of this invention are described in the context of producing quantities of rapidly solidified, ultra-fine metal and alloy powders. This invention is equally applicable to the atomization of any liquid melt from which a fine solid powder or aerosol can be generated. This includes but is not restricted to iron and steel, superalloys, aluminum, copper, precious metals, and associated alloy systems. (The term "melt", as used in this description and the following claims, will be understood to include any liquid suitable for atomization in accordance with the present invention.) Item numbers are uniform throughout the description of the device.
- Referring now to Figure 1, a perspective view is shown of the atomization system, consisting of the
gas atomization device 100, crucible or furnacemelt containment vessel 200, and fine powder collection system. The letter consists of arapid cooling chamber 300,cyclone separator 400, second stage finepowder removal device 500,ultra-fine powder filter 600, andgas pump 700. - Gas atomization dies, per se, are known in the art and consist of an orifice through which the melt passes, and one or more high pressure gas jets for breaking up and atomizing the melt as it passes out of the die orifice. The gas atomization die 100 can be of subsonic. supersonic, or ultrasonic design. A subsonic gas atomization device is illustrated here in Figure 1. Ultra-fine
metal powder 140 is produced by passingpressurized gas 150, such as argon, nitrogen, etc., through the atomization die 100. Thisatomization gas 150 is delivered to the atomization die 100 via a gas delivery passage 160 through the body of the die 100. This high pressure gas 150 exits the atomization die 100 at high velocity, thereby aspirating themelt 210 through the atomization die orifice 111. When aspirated (or forced) through thedie 100, themolten metal 210 is atomized and rapidly cooled by the impinging, high velocity, atomization gas jets 114 (Figure 2). During this very short rapid cooling and solidification period, the atomizeddroplets 140 are further disintegrated into ultra-fine powders by the rapid generation of gas within the droplets. The gas, which "explosively" disintegrates the already atomized droplets, is soluble in the liquid melt but its solubility is a strong function of temperature and, therefore, gas is rapidly generated within each droplet as it cools upon exiting the atomization die 100. The solubility of nitrogen in iron is illustrated in Figure 4, by way of example. The solubility of nitrogen in iron is a function of temperature, and changes abruptly and significantly at specific temperatures where phase transitions occur. Referring to Figure 4, one can expect significant soluble gas evolution either upon rapidly cooling of the melt and/or when structural phase changes occur in the melt at specific transition temperatures. Consequently, the rate of soluble gas evolution and subsequent extent of soluble gas atomization is a function of the rate at which the melt is cooled. - In Figure 1, the
melt 210 to be atomized is located above theatomization die 100 and therapid cooling chamber 300. In practice, theatomization die 100 could access the crucible orfurnace 200 from the bottom, top, or side. It is also possible for thecrucible 200 andatomization die 100 to be located entirely within thecooling chamber 300. - Before the atomization process begins, the
melt 210 must be saturated with asoluble gas 220. If thecrucible 200 is closed, themelt 210 can be supersaturated by holding thesoluble gas 220 at elevated pressure above themelt 210. Various gases, including argon, nitrogen, and hydrogen, which are soluble in liquid metals, can be used. These soluble gases can be introduced into themelt 210 via a gas bubbling mechanism and/or can simply be held at static pressure over themelt 210 if thecrucible 200 is closed. As the melt exits the gas atomization die 100 and begins to cool rapidly, the soluble gas comes out of solution within the atomized melt droplets, expands rapidly, and causes the metal to further disintegrate into ultra-fine powder. - It is known in the art of soluble gas atomization that a melt can be supersaturated with soluble gas by pressurizing the melt containment vessel with the gas to be dissolved. In such systems, the head pressure is used to propel the melt material through a transport tube into an evacuated chamber. The gas is evolved from the melt as it exits the transport tube into the evacuated chamber due to the low partial pressure of the soluble gas surrounding the melt stream in the evacuated chamber. In such cases, the dissolved gas expands within the melt as it leaves the transport tube causing it to be atomized. The abrupt change in the over-pressure of the soluble gas causes the gas to be evolved from the melt and atomizing it. In expanding, the gas cools thus cooling the melt. This cooling rate is low, typically 10 to 102 °K/s.
- In the present invention however, the melt containing soluble gas is atomized and rapidly cooled by the gas atomization process. The melt is atomized into a
chamber 300 which need not be evacuated. Because the melt is rapidly convectively cooled by the impinging gas atomization jet, the evolution of soluble gas from the melt is driven predominantly by the temperature change of the atomized droplets. Soluble gas will be evolved in especially significant quantities at phase change temperatures such as correspond to the solidus-liquidus line. - This unique combination of the gas atomization and temperature versus pressure driven soluble gas atomization processes, which generates ultra-fine powders, is the essence of this invention. For example, when this device and method is applied to carbon steel, ultra-fine powder with an average particle size of less than 1 µm is generated. This ultra-fine carbon steel powder is an order of magnitude smaller than the smallest metal powder (greater than 10 pm) produced by any other commercially viable technique.
- The
melt 210 may containsoluble gases 220 and/or elemental components which will combine, on cooling of themelt 210, to generate a gas. One example of this latter case is carbon and dissolved oxygen in carbon steel. Upon cooling, the carbon reacts with the dissolved oxygen to form carbon monoxide gas. Since carbon monoxide only has a negligible solubility in solid carbon steel, it is rapidly evolved upon cooling and solidification and can generate tremendous internal gas pressures if trapped within the solid steel. Hence, this type of gas generation upon cooling of the melt is very desirable in the present invention. This phenomena of carbon monoxide generation during cooling or solidification of carbon steel is well known in steelmaking. It is generally avoided by "killing" the melt will aluminum which reacts with the oxygen to form solid aluminum oxide particulates. - A soluble gas may also be generated within the
melt 210 by introducing a specific constituent which reacts in themelt 210 to generate a soluble gas. One example of this method is steam, which, when bubbled through carbon steel, reacts to form soluble hydrogen and oxygen. As the melt cools, the oxygen is available to combine with carbon present in the steel to form insoluble carbon monoxide gas. In addition, the hydrogen will also leave solution upon cooling of the melt and contribute to the soluble gas atomization component of the current atomization invention. A further example would be the addition of methane to carbon steel, for example. Here the methane reacts to form soluble carbon and hydrogen in the melt. - Figure 1 also illustrates the powder collection system. This consists of a
rapid cooling chamber 300 within which theultra-fine powders 140 are generated and rapidly cooled by the impinging atomization gas jet. Thiscooling chamber 300 can be designed to accommodate multiple atomization dies. The cooling chamber's dimensions are such so as to allow thepowders 140 to solidify and cool sufficiently before passing to thecyclone separator 400. The atomized powders are carried by the atomization gases, or pneumatically transported, from the coolingchamber 300 to thecyclone separator 400. Powders in the micron size range and larger are removed from the transport gas by thecyclone separator 400. A parallel series of cyclone separators could be used to selectively separate thepowder 140 by average particle size. -
Ultra-fine powder 140 in the submicron particle size range will pass through thecyclone separator 400 with the carrier gas to the second stagepowder recovery unit 500. This unit may consist of magnetic. electrostatic, impact, or solution separator. Any powder failing to be removed by the second stagepowder recovery unit 500 will pass on to afilter 600 in the gas transfer line. Thisfine grade filter 600 will remove all powder residue from theatomization gas 150 before it passes on through thegas pump 700 and out of the system. -
- Figure 2 illustrates one specific subsonic gas atomization die 100 design used in this invention. High pressure
inert gas 150 is supplied to the atomization die 100 via a conduit 160. Theinert gas 150 fills theannular core 112 of the atomization die 100 and passes at high velocity into therapid cooling chamber 300 via an inclinedannular gas nozzle 113 which circumscribes the top of the atomization die orifice 111. The passage of the high velocityinert gas 150 over the top of the atomization die orifice 111 reduces the pressure within the orifice passage 111, assistingliquid metal 210 to pass through the orifice 111. Theliquid metal 210 is also aspirated through the orifice 111 with the assistance of the pressure of theliquid metal bath 210. As the aspirated liquid metal exits the orifice 111 and enters thecooling chamber 300, it is atomized by the combined effect of the impinginggas jet 114 and the "explosive" soluble gas atomization effect created by the gas evolved during the rapid cooling of themelt 210. The atomizedliquid metal 140 is rapidly solidified by this high velocity, expandinggas jet 114. The inclination angle of the impinging gas jet can be modified from one liquid metal to another to optimize the aspiration effect on theliquid melt 210 and the subsequent atomization of the liquid metal jet. Theatomization gas 150 serves to carry the finely atomized powder creating ametal aerosol 140 which flows out of thecooling chamber 300 and on into thepowder recovery cyclone 400 and secondstage recovery unit 500. - Figure 3 illustrates a further embodiment of the atomization die 100. In this embodiment, the gas atomization die 100 is fitted with an
orifice heating element 115 which eliminates any orifice freeze-off problem. The heating element consists of asimple metal coil 115 which is wrapped around thecentral orifice sleeve 116. The particular metallic heating element selected is determined by the operating temperature requirements of the melt to be atomized. For example, the atomization die 100 for a tin melt can be maintained above the melting point of tin with nichrome heater element, whereas for a ferrous system a tungsten or molybdenum filament may be suitable. The heat generated by theheating coil 115 serves to insulate thecentral orifice sleeve 116 from the cooling effect of the inert gas passing through theannular nozzle 113 of thedie 100. Theheating coil 115 may be connected to a heat control device so as to provide only enough heat to ensure that the melt being atomized remains above its melting temperature as it passes through the orifice 111, or to control the rate or extent of metal build-up within the orifice 111. - Figures 2 and 3 show details of a subsonic gas atomization die 100 which may be used in the initial atomization/cooling step of the present invention. This die design may be used with a range of orifice 111 and
annular nozzle 113 sizes. In an earlier patent application described in U.S. patent application number 522,913, filed August 12, 1983, this design incorporates an orifice 111 as small as a fraction of millimeter (mm). In this invention, therefractory die 100 illustrated in Figure 2 has been used to demonstrate the unique gas atomization/soluble gas atomization process with acarbon steel melt 210 using a 0.75 mm orifice 111. However, the orifice 111 could be enlarged considerably, with thedie 100 retaining its ultra-fine powder generation capability as long as an appropriate atomization gas flow to melt flow ratio of at least approximately 10 to 1 is maintained. The use of an enlarged die orifice 111 facilitates the production of commercial quantities of the ultra-fine powders. - The soluble gas/gas atomization process, according to the present invention, for generating ultra-fine, rapidly solidified powders is initiated by first introducing a
soluble gas 220 into themelt 210, Figure 1. As shown in this embodiment, the melt crucible orfurnace 200 can be contained within apressure vessel 250. The amount ofsoluble gas 220 in themelt 210 can be increased by maintaining the soluble gas at high pressure over themelt 210. Arelief valve 260 is desirable to avoid building up excessive pressure within thevessel 250. After the melt has been saturated withsoluble gas 220, the stopper rod 270, which restricts melt flow to the atomization die 100, is withdrawn. Simultaneously, highpressure atomization gas 150 is supplied to the atomization die 100. The melt flow through the atomization die 100 is assisted by gravity, the head pressure within thecontainment vessel 250, and the aspiration effect of theatomization gas 150 through thedie 100. As themelt 210 exits thedie 100 it is atomized by the impinginggas jet 114, Figure 2. This gas atomization process not only atomizes the metal exiting thedie 100, but also conductively cools the atomized droplets as well. Consequently, the soluble gas within the melt comes out of solution rapidly, expands, and further disintegrates the atomized droplets intoultra-fine powder 140. The atomizedultra-fine powder 140 in thecooling chamber 300 is carried by the gas used in the atomization process. Thisfine powder aerosol 140 exits the cooling chamber and enters thecyclone separator 400 where all powder particles larger than roughly a micron in diameter are removed. The submicron powder is transported by the gas flow from thecyclone 400 to the secondarypowder collection device 500. This unit may consist of a magnetic, electrostatic, fluid. or other fine particle separator. Residual powders are removed from the carrier gas by an in-linefine particle filter 600. Thegas pump 700 aids in initiating the gas flow from the coolingchamber 300 and on through the powder removal and collection system. - It will be appreciated that while the invention has been described in terms borrowed from the soluble gas atomization and from the gas atomization of conventional techniques, the invention involves uttra-find atomization by driving soluble gas from an atomizing melt through cooling, and, as such, includes within its scope a variety of techniques and devices for achieving this result as limited only by the following claims.
Claims (20)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US06/634,785 US4626278A (en) | 1984-07-26 | 1984-07-26 | Tandem atomization method for ultra-fine metal powder |
US634785 | 1984-07-26 |
Publications (3)
Publication Number | Publication Date |
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EP0175078A2 true EP0175078A2 (en) | 1986-03-26 |
EP0175078A3 EP0175078A3 (en) | 1987-02-04 |
EP0175078B1 EP0175078B1 (en) | 1990-11-14 |
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EP19850108528 Expired - Lifetime EP0175078B1 (en) | 1984-07-26 | 1985-07-09 | Device and method for production of ultra-fine, rapidly solidified, metal powders |
Country Status (4)
Country | Link |
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US (1) | US4626278A (en) |
EP (1) | EP0175078B1 (en) |
JP (1) | JPS61106703A (en) |
DE (1) | DE3580554D1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0504382A1 (en) * | 1990-10-09 | 1992-09-23 | Univ Iowa State Res Found Inc | A melt atomizing nozzle and process. |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5024695A (en) * | 1984-07-26 | 1991-06-18 | Ultrafine Powder Technology, Inc. | Fine hollow particles of metals and metal alloys and their production |
DE3622123A1 (en) * | 1986-07-02 | 1988-01-21 | Dornier System Gmbh | METHOD AND DEVICE FOR PRODUCING COMPOSITE POWDERS |
US4869469A (en) * | 1987-04-24 | 1989-09-26 | The United States Of America As Represented By The Secretary Of The Air Force | System for making centrifugally cooling metal powders |
US4793853A (en) * | 1988-02-09 | 1988-12-27 | Kale Sadashiv S | Apparatus and method for forming metal powders |
GB8813338D0 (en) * | 1988-06-06 | 1988-07-13 | Osprey Metals Ltd | Powder production |
US5039477A (en) * | 1989-06-02 | 1991-08-13 | Sugitani Kinzoku Kogyo Kabushiki Kaisha | Powdered metal spray coating material |
US5114470A (en) * | 1990-10-04 | 1992-05-19 | The United States Of America As Represented By The Secretary Of Commerce | Producing void-free metal alloy powders by melting as well as atomization under nitrogen ambient |
US5656061A (en) * | 1995-05-16 | 1997-08-12 | General Electric Company | Methods of close-coupled atomization of metals utilizing non-axisymmetric fluid flow |
US5601781A (en) * | 1995-06-22 | 1997-02-11 | General Electric Company | Close-coupled atomization utilizing non-axisymmetric melt flow |
US5870524A (en) * | 1997-01-24 | 1999-02-09 | Swiatosz; Edmund | Smoke generator method and apparatus |
US5954112A (en) * | 1998-01-27 | 1999-09-21 | Teledyne Industries, Inc. | Manufacturing of large diameter spray formed components using supplemental heating |
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MXPA06011747A (en) * | 2004-04-12 | 2007-01-16 | Polymer Group Inc | Method of making electro-conductive substrates. |
JP2007232432A (en) * | 2006-02-28 | 2007-09-13 | Hitachi Ltd | Chimney of natural circulation type boiling water reactor |
CN103611942B (en) * | 2013-12-10 | 2015-10-14 | 河北联合大学 | The method of high pressure melting atomization nitrogen quenching device and production samarium Fe-N Alloys powder thereof |
EP3714970A1 (en) * | 2019-03-28 | 2020-09-30 | Catalytic Instruments GmbH & Co. KG | Apparatus for the production of nanoparticles and method for producing nanoparticles |
FR3095861B1 (en) | 2019-05-09 | 2021-06-04 | Commissariat Energie Atomique | DEVICE FOR ANALYSIS OF A LIQUID MATERIAL BY LIBS SPECTROSCOPY TECHNIQUE WITH ATOMIZATION |
CN110181069B (en) * | 2019-07-08 | 2023-01-31 | 华北理工大学 | Method for preparing high-nitrogen steel powder by adopting gas atomization method |
DE102021114987A1 (en) | 2021-06-10 | 2022-12-15 | Topas Gmbh Technologieorientierte Partikel-, Analysen- Und Sensortechnik | Device for generating a conditioned aerosol |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1194444A (en) * | 1967-12-15 | 1970-06-10 | Homogeneous Metals | Method and Apparatus for making Metal Powders |
EP0150755A2 (en) * | 1984-01-25 | 1985-08-07 | Nyby Uddeholm Powder AB | Process and installation for the preparation of metal powder |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2371105A (en) * | 1945-03-06 | Atomization process | ||
US3840623A (en) * | 1971-06-01 | 1974-10-08 | Steel Corp | Atomization of liquid materials and the subsequent quenching thereof |
JPS5123463A (en) * | 1974-05-17 | 1976-02-25 | Hitachi Cable | Fuintsukichuubu no fuinhenkeiyokogu |
GB1604019A (en) * | 1978-05-31 | 1981-12-02 | Wiggin & Co Ltd Henry | Atomisation into a chamber held at reduced pressure |
US4192673A (en) * | 1978-12-19 | 1980-03-11 | Hyuga Smelting Co., Ltd. | Method of manufacturing granulated ferronickel |
-
1984
- 1984-07-26 US US06/634,785 patent/US4626278A/en not_active Expired - Lifetime
-
1985
- 1985-07-09 DE DE8585108528T patent/DE3580554D1/en not_active Expired - Fee Related
- 1985-07-09 EP EP19850108528 patent/EP0175078B1/en not_active Expired - Lifetime
- 1985-07-25 JP JP60163109A patent/JPS61106703A/en active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1194444A (en) * | 1967-12-15 | 1970-06-10 | Homogeneous Metals | Method and Apparatus for making Metal Powders |
EP0150755A2 (en) * | 1984-01-25 | 1985-08-07 | Nyby Uddeholm Powder AB | Process and installation for the preparation of metal powder |
Non-Patent Citations (2)
Title |
---|
Journal of Metals, April 1984 * |
Metals Handbook, 9th ed., vol. 7, Powder Metallurgy * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0504382A1 (en) * | 1990-10-09 | 1992-09-23 | Univ Iowa State Res Found Inc | A melt atomizing nozzle and process. |
EP0504382B1 (en) * | 1990-10-09 | 1997-05-28 | Iowa State University Research Foundation, Inc. | A melt atomizing nozzle and process |
Also Published As
Publication number | Publication date |
---|---|
DE3580554D1 (en) | 1990-12-20 |
EP0175078A3 (en) | 1987-02-04 |
US4626278A (en) | 1986-12-02 |
EP0175078B1 (en) | 1990-11-14 |
JPS61106703A (en) | 1986-05-24 |
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